chocochunk

As a side project, I have been working with Mykle Hansen to add some heads-up visuals at the annual Lightbar. This year there is a 5/8’s scale dome for all the artists to display their light oriented sculptures. We have had quite a few donations and now have 6 computers and 7 loaned projectors. We have stitched together a very large high resolution, distortion corrected visuals display. With lightbar’s opening week already behind us, this project will be on display late February and open to the public. Lightbar is around 27th and Killingsworth, you can’t miss it.

Lightbar home

I am continuing the development for the “Caddy” video rig with the addition of the popular Arduino board. As I have documented previously on my blog, the Caddy is a video camera rig that drives on a 2″ track to tow a helium blimp outfitted with a 13-ounce Sony camera.

The Arduino, an open source electronics developers board, has a usb port and software for flashing code. Very accessible and well supported by its fans, it should be a perfect addition to the Caddy since it supports both analog and digital I/O and there are code libraries available to make use of servos, which are small yet accurate motors with lots of torque. In this application I will make use of an electronic speed control similar to a servo. Once the code is worked out so that my sensor and speed controls work together correctly, the main chip can then be removed from the Arduino and placed in a more streamlined circuit at a fraction of the cost. And then the Arduino will be ready for my next development project.

The video Caddy tends to slow down a bit in the turns of the track due to the wheels cinching. With a microprocessor on board, I will be able to instruct the motor’s speed control to increase if there is a loss of speed relative to the throttle on my radio controller. Since I am towing the blimp with three 6-pound fishing lines, it will be very critical to have a smooth-moving “train” with plenty of mass. To keep the speed steady, I will print out some sheets with equally spaced black lines and glue them to my track. To keep these calibration lines accurate, I will use Adobe Illustrator; with its large workspace I will be able to make accurate lines out to the 9′ radius of the Caddy track. I have some optical sensors that are designed with this application in mind. The sensor contains two readers in one case. By timing the difference between the light and dark lines, the Arduino will determine the velocity at which the Caddy is moving. And the Arduino will sit between the radio and the speed control, as seen in this graphic.

I have a Mac mini that I purchased initially with the intention of mounting in the dash of my van. While I had it all worked out how I would beam podcasts to the van in my driveway while I was sleeping, I had not worked out the burning rings that kept the “Atari van” from passing Portland’s strict DEQ standards. My interest in wrenching ends with the vintages. In the coming weeks I will write about some great uses for this aesthetically pleasing low-cost box from Apple, which still maintains mass crowd appeal.

Apple has an advanced video processor built into the core of the OS. This is referred to as CoreVideo. It is like a low-level OpenGL, which is a graphics architecture that allows many modelers and shaders to work smoothly. Think of Google Sketchup to get an idea of where OpenGL excels. With the newest Apple OS, the kind developers have enhanced some of the tools surrounding CoreVideo. I would like to share one of these fantastic tools–Quartz Composer–one of my favorite hobby tools that allows you to tap into the power of the CoreVideo with a reasonable modularity for anyone to tackle in an afternoon.

The Mac mini has been built with either Motorola’s PowerPC or the newer Intel chipsets. While an Intel would be nice, the shortcomings of the graphics really make this more of a hobby machine. In many cases Mac minis have been popular as servers due to their size and efficiency. As a longtime creative PC slave (money decisions, don’t flame the meek!) there are a few differences I have noticed here. First, Apple power saving works, regardless of what is attached. My mini will try to run anything, and features are disabled to make the program run reasonably. I like that, so the box stays. So how do I use it? Allow me to show and tell.

Quartz Composer is used by many people for some very different uses. To install it, you must find your original Apple OS CD and install the Core X components (check the web for a guide). Quartz files can be used as screen savers natively, and there are some unique capabilities such as the RSS feed puller that make Quartz more like Max/MSP or other “if you can dream it, there’s a way” tools for artists. Quartz files can integrate deep into Apple’s flagship software Quicktime. And for those media-savvy blurkers, I don’t need to tell you that Quicktime is a part of just about everything Apple. From Ableton Live, to screen savers, even flash and Adobe–on some level every application in use today has some sort of ability to incorporate Quicktime. Quartz can make it easy to write code for these programs in a spaghetti environment that allows you to keep your mind on what you want to do, and not how to do it.

Here in my photo I have adapted kineme’s little module for midi controllers. With any midi music controller, you can control your transitions and effects with much more precision while being able to change several things at once. Much more fun than pushing a mouse. What you see in the “inspector,” which is the window from where all options are placed, is a simple conversion formula I used to add more control options from my midi controller. Midi CC messages are very common for any midi-capable device; however, the slider range is typically integers 0-127. With many video and audio software the value scales from -1 to 1, which is basically a DC or audio range. With this you can connect your controller to any value plug. Or you can send it to your audio card if you want to control hardware or attach relays to your audio card… really powerful stuff from a free package!